This is all biological evolution, we are a surviving species because our
ancestors consumed natural sugars from fruits and did not die. Thus we
are not wired to avoid sugar or even consider it as a toxin. With the
advent of artificial/processed sugars the story is entirely different.
We consume it because we don't have immediate negative
biological/physiological consequences, but overtime those sugars are
related to increasing rates of diabetes and they will eventually kill
us.

(3) Another article describing the toxicity of sugar.
Here's the highlights:
-The study found "medical inference of causation by linking dose (the more sugar that’s
available, the more occurrences of diabetes); duration (if sugar is
available longer, the prevalence of diabetes increases); directionality
(not only does diabetes increase with more sugar, it decreases with less
sugar); and precedence (diabetics don’t start consuming more sugar;
people who consume more sugar are more likely to become diabetics)." This is an incredibly sound study that put into check as many controls as possible (basically the best laid out study aside from some longitudinal randomized controlled double-blind study performed in-house.)
-"for every 12 ounces of sugar-sweetened beverage introduced per person
per day into a country’s food system, the rate of diabetes goes up 1
percent"
-"all calories are not created equal...calories give off
the same amount of energy when burned, but your body treats sugar
calories differently, and that difference is damaging."
-"Metabolic syndrome is a
result of insulin resistance, which appears to be a direct result of
consumption of added sugars."

Bottom line: sugar alone can cause diabetes regardless of whether you are obese or not (obesity also causes diabetes but that's a different story.) The question for many readers now might be "how do I deal with this?" I'll dive deeper into this again, but as with any highly addictive substance there are many ways two of which are: